There’s Blood in My Urine – Why Drug Interactions Matter

Imagine that you wake up one morning not feeling too well. You begin to cough up green stuff and have some pain in your chest. You go to a doctor you don’t usually see and he diagnoses you with a chest infection. He asks you what previous medications you’re on but you didn’t bring them and can’t remember. He’s about to give you a prescription for augmentin, a penicillin. You quickly remember that you’re allergic to penicillin. He changes the prescription to clarithromycin.

You take this to your pharmacist who gives you the tablets with instructions on how to take it. You return home, take the medications for the next 3 days and then you start to see blood in your urine. You quickly search online for why this could be and you soon find that the clarithromycin your doctor put you on can make you pee blood if you usually take Warfarin.

A drug dictionary is where one would ordinarily think to go look for what medications mean and what they do. Pharmacists, however, do not use a drug dictionary per se. What they use is referred to as a formulary. The most commonly used formulary in most parts of the English speaking world, especially in the Commonwealth nations is the British National Formulary, abbreviated to the BNF.

Another important reference book is ‘Martindale, the complete drug reference’. It contains over 185,000 preparations and comes in 2 large copies. It can, however, be quite expensive and bulky. Hence the BNF is more widely used.

When you go to a pharmacy with a prescription for a new drug like clarithromycin, the pharmacist would need to collect a list of your previous medication. This enables her check to see if this new tablet has any drug-drug interaction with your regular tablets. In the instance above, if the pharmacy had your drug history, which they should, they would be able to cross check and detect that clarithromycin would lead to you bleeding while on warfarin. They would hence be able to advise you appropriately.

When filling prescriptions it’s important to reveal what drugs you usually take. Insist also that the pharmacy keeps a record. When adding new tablets, ask them to make sure no interactions take place with your usual medications. This process can often take a few minutes so be patient. It’s better to wait and get the right medications and advice than to rush out only to end up being rushed later to the hospital.

To help, refer your pharmacist to WellaHealth, we help them keep your drug records and check that all the medications you’re on don’t interact and are safe. If you’re a pharmacist reading this, get in touch by putting your phone number on our website and we will give you a call to set you up and start providing improved pharmaceutical care services to your patients.